apt-maven-plugin with maven-release-plugin fails (NPE)

[guersel]

If I use the apt-maven-plugin in combination with the maven-release-plugin then a NullpointerException will be thrown:

[INFO] [INFO] --- apt-maven-plugin:1.1.3:process (default) @ [myProject]---
[INFO] An exception has occurred in the compiler (1.8.0-internal). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport)  after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report.  Thank you.
[INFO] java.lang.NullPointerException
[INFO]  at com.sun.tools.javac.processing.JavacProcessingEnvironment$ComputeAnnotationSet.scan(JavacProcessingEnvironment.java:797)
[INFO]  at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.findAnnotationsPresent(JavacProcessingEnvironment.java:993)
[INFO]  at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.<init>(JavacProcessingEnvironment.java:927)
[INFO]  at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.next(JavacProcessingEnvironment.java:933)
[INFO]  at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1199)
[INFO]  at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1182)
[INFO]  at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:868)
[INFO]  at com.sun.tools.javac.main.Main.compile(Main.java:535)
[INFO]  at com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:141)
[INFO]  at com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:150)

This happens if I try to release on jenkins with Java 8 (IBM SDK 64bit). A normal build without trying to release is successful. I use version 1.1.3 of the apt-maven-plugin and version 2.5.1 of the maven-release-plugin, configuration of the apt-maven-plugin looks like:

    <plugin>
            <groupId>com.mysema.maven</groupId>
                <artifactId>apt-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>generate-sources</phase>
                        <goals>
                            <goal>process</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>${basedir}/target/generated-sources/java</outputDirectory>
                            <processor>com.mysema.query.apt.jpa.JPAAnnotationProcessor</processor>
                        </configuration>
                    </execution>
                </executions>
    </plugin>

The release build is successful if I debug remotely via Eclipse, maybe there is a timing issue between the release- and apt-plugin?

[Shredder121]

Could you setup a minimalistic project that we can also debug?
I don't use eclipse, but we'll see if it is also reproducible via other means.

[guersel]

Thank you for the very fast response.
Unfortunately I am not able to setup a minimalistic projects which fails in the same way. It seems that this issue is project specific.

[guersel]

I solved the issue by just waiting a few seconds before executing the apt-maven-plugin. Obviously the release plugin creates threads which are in access conflict with the apt-maven-plugin. Maybe someone has another explanation.

[ddebrunner]

FYI - I'm seeing the same stack trace in a non-maven project. In my case it seems to be related to annotation processing generating a source file with annotations (e.g. @javax.annotation.Generated).

I was also seeing it intermittently, indicating there is some timing issue.

A simple case outside of our source code did not reproduce the issue.

[Shredder121]

I think that (as @guersel also thought) the release plugin uses a fork of the build reactor to do some logic, and therfore it theoretically could cause timing issues. (this explains the intermittent problems)
I'll look into it.